This is one of those cases in which no rain may be falling and yet very dangerous flash floods can occur. During the past winter season, a tremendous snowpack built up in the Rockies. In the Wasatch Mountains of Utah, over 600 inches of snow fell since October. Quite impressive was the 14 feet of snow that fell in Alta, Utah during a 14-day stretch at the end of March and beginning of April.

All that snow still covering the mountains contains a lot of water, and when it melts too fast, like it did early this week, runoff becomes excessive. The flow turns small streams and babbling brooks into raging torrents that can easily sweep unwary hikers to their doom.

An even greater threat to lives are those usually dry mountainside ravines.

These channels are inviting hiking territory, since they have fewer obstructions. But remember, these are dry washes that can suddenly fill with fast-moving water during rapid thaws.

Story by AccuWeather.com Expert Senior Meteorologist John Kocet.